How Lightning Locker Uses the Proxy Object
Lightning Locker uses the standard JavaScript Proxy object to filter a component’s access to underlying JavaScript objects. The Proxy object ensures that a component only sees DOM elements created by a component in the same namespace.
You can interact with a Proxy object in the same way as you interact with the raw JavaScript object, but the object shows up in the browser’s console as a Proxy. It’s useful to understand Lightning Locker’s usage of Proxy if you drop into your browser’s debugger and start poking around.
When a component creates a JavaScript object, Lightning Locker returns the raw JavaScript object. When Lightning Locker filters the object, it returns a Proxy object. Some scenarios where Lightning Locker filters an object and returns a Proxy object are:
- Passing an object to a Lightning web component (LWC) or an Aura component in a different namespace.
- Passing an object from an Aura component on API version less than 40.0 to the method of a component on API version greater than or equal to 40.0.
- Calling
cmp.get() to retrieve an Aura component attribute value that you set with the value of a native JavaScript object or array. The object or array isn’t filtered when it’s originally created.
When you access these objects, Lightning Locker returns a Proxy object.
- Any object that implements the HTMLCollection interface
- A
SecureElement object, which represents an HTML element.
See Also
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